Ocular toxoplasmosis after autologous peripheral-blood stem-cell transplantation

Clinical characteristics and incidence of toxoplasmosis after autologous hematopoietic stem cell transplantation: A retrospective study and literature review

BACKGROUND

Toxoplasmosis is a rare but life-threatening infection occurring in immunocompromised hosts, including allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. However, thus far, the clinical features and incidence of toxoplasmosis in autologous HSCT (auto-HSCT) recipients remain unknown. This retrospective survey aimed to analyze 152 patients who received auto-HSCT between 1998 and 2017.

METHODS

Serological tests for Toxoplasma gondii-specific IgG were performed on 109 (71.7%) recipients, and 12 pre-HSCT recipients (11%) were Toxoplasma seropositive. Among the 12 recipients, three who did not receive trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis developed cerebral, pulmonary or disseminated toxoplasmosis due to reactivation after auto-HSCT and died despite treatment.

RESULTS

The incidences of toxoplasmosis were 2% and 25% among 152 auto-HSCT recipients (five recipients received auto-HSCT two times) and 12 pre-HSCT Toxoplasma seropositive recipients, respectively. Further, we conducted a literature review and identified 21 cases of toxoplasmosis following auto-HSCT. In these previous cases, the mortality rate was high, especially for pulmonary and disseminated toxoplasmosis. Our findings suggest that, similar to toxoplasmosis after allo-HSCT, toxoplasmosis after auto-HSCT is a fatal complication.

CONCLUSIONS

Serial screening of T. gondii-specific IgG before HSCT could contribute to the detection of Toxoplasma reactivation and allow for prompt diagnosis and treatment. The present study is the first to reveal the incidence of toxoplasmosis after auto-HSCT among seropositive patients in Japan.

Toxoplasma Encephalitis following Tandem Autologous Hematopoietic Stem Cell Transplantation: A Case Report and Review of the Literature

Infection with Toxoplasma gondii is a rare but often fatal complication in hematopoietic stem cell transplantation (HSCT) recipients. Most cases have been reported in allogeneic (allo-) HSCT recipients, with only narrative reports following autologous HSCT (ASCT). We report the case of a 58-year-old Caucasian male presenting with toxoplasma encephalitis following tandem ASCT for myeloma and successfully treated with diagnosis by polymerase chain reaction analysis of cerebrospinal fluid. He was treated with sulfadiazine and pyrimethamine (with leucovorin) followed by pyrimethamine and atovaquone as secondary prophylaxis while receiving subsequent therapy for progressive multiple myeloma. Toxoplasmosis is a potential complication in allo-HSCT as well as ASCT recipients and should be considered in any post-HSCT patient with neurological dysfunction. Rapid diagnosis and immediate antimicrobial treatment are essential to avoid morbidity and mortality.

Toxoplasma prophylaxis in haematopoietic cell transplant recipients: a review of the literature and recommendations

PURPOSE OF REVIEW

Toxoplasmosis in haematopoietic cell transplant (HCT) recipients is associated with high morbidity and mortality rates. Prophylaxis following HCT is recommended for high-risk pre-HCT toxoplasma-seropositive (pre-HCTSP) recipients. However, there is no agreement or consistency among programmes on whether to adopt prophylaxis or not, or if used, on the chosen antitoxoplasma prophylactic regimen. This review discusses the role of prophylaxis, and preemptive treatment, for toxoplasmosis in the setting of HCT.

RECENT FINDINGS

Approximately two-thirds of toxoplasmosis cases following HCT are reported in allogeneic pre-HCTSP (allo pre-HCTSP) patients. This finding confirms a major role of reactivation of latent infection in the pathogenesis of toxoplasmosis in this patient population. Toxoplasma disease-related mortality in allo pre-HCTSP patients was reported at 62%, but it can be significantly decreased with early detection and treatment of toxoplasma infection. There are no randomized trials comparing the efficacy of different prophylactic agents to prevent toxoplasmosis after HCT. Several observational studies have demonstrated the efficacy of trimethoprim-sulfamethoxazole (TMP/SMX) in decreasing the incidence of toxoplasmosis following HCT. There is limited information regarding efficacy of other prophylactic agents. Preemptive treatment using routine blood PCR monitoring seems to be beneficial in detecting infection early and preventing disease in several observational studies and has been adopted for allo pre-HCTSP HCT patients when universal prophylaxis is not possible.

SUMMARY

Universal prophylaxis with TMP/SMX in allo pre-HCTSP patients should be implemented by all transplant programmes. Preemptive treatment with routine blood PCR monitoring is an option if prophylaxis cannot be used.

Determining Toxoplasma high-risk autologous and allogeneic hematopoietic stem cell transplantation patients by systematic pre-transplant PCR screening of stem cell originated buffy coat

The diagnosis of Toxoplasma infection or disease in hematopoietic stem cell transplantation (HSCT) patients is achieved mainly by PCR screening; however screening did not find wide field of use in practice due to costly expenditures of PCR. This study aimed to determine patients at high risk of Toxoplasma infection or disease before transplantation by stem cell originated buffy coat PCR and subsequently to screen them. Buffy coats collected from 12 autologous and 18 allogeneic HSCT patients' donors were investigated by PCR before transplantation. After transplantation, blood and sera collected at fixed time intervals were screened by two PCR methods and serological assays. Screening results first time assessed a toxoplasmosis incidence level as 25% in autologous HSCT patients and increased incidence level in allogeneic HSCT patients to 22%. Importantly, buffy coat PCR was first time performed before transplantation, to determine the risk of toxoplasmosis. Buffy coat PCR results showed that four patients were at high risk of toxoplasmosis before transplantation. After transplantation, these patients experienced toxoplasmosis. In conclusion, for the determination of patients at risk of toxoplasmosis, clinicians should consider buffy coat PCR in combination with serology before transplantation. After transplantation, PCR screening can be initiated in high risk patients upon clinical suspicion.

Cerebral toxoplasmosis after autologous peripheral blood stem cell transplantation

Toxoplasmosis appears to be a rare opportunistic protozoal infection following haematopoietic stem cell transplantation (HSCT). Most cases have been reported in allogeneic HSCT recipients, with only anecdotal reports of infection occurring after autologous transplantation. Reported here is the case of a patient who developed cerebral toxoplasmosis following autologous peripheral blood stem cell transplantation for non-Hodgkin's lymphoma.

Toxoplasmosis after hematopoietic stem cell transplantation

Forty-one cases of toxoplasmosis were diagnosed in 15 European transplantation centers in patients who had undergone allogeneic hematopoietic stem cell transplantation (HSCT) from 1994 through 1998. Most patients (39 [94%]) were seropositive for Toxoplasma gondii before they underwent transplantation, and 30 (73%) had developed moderate to severe acute graft-versus-host disease before they developed toxoplasmosis. Thirty-five (85%) patients had Toxoplasma disease with evidence of organ involvement, whereas 6 (15%) patients had Toxoplasma infection, as defined by fever and a positive polymerase chain reaction (PCR) finding for T. gondii in blood. Nine patients were diagnosed at autopsy. Thirty patients (73%) had not received antimicrobial prophylaxis with anti-Toxoplasma activity after undergoing transplantation. The median day of onset of disease after HSCT was 64. Twenty-two (63%) patients died from toxoplasmosis, and 23 (66%) received adequate anti-Toxoplasma therapy for > or =3 days. Among these 23 patients, 11 (48%) showed a complete response and 3 (13%) showed improvement. In univariate and multivariate analyses, having received adequate therapy and experiencing late infection (>63 days after HSCT) were associated with a lower risk of dying from toxoplasmosis. Toxoplasmosis after HSCT is a severe infection with a high mortality rate even when diagnosed soon after HSCT, and PCR may help establish the diagnosis earlier.